I tried to use a simple `QTimer` object on my window widget so that I can calculate the elapsed time a method takes to complete.
But to my astonishment! the timer was blocked until the method completes execution! i.e when the method in question ends, the timer starts ticking!!
Here is a sample code to demonstrate what I wrote:
Qt Code: 
  1. #ifndef MAINWINDOW_H
  2.     #define MAINWINDOW_H
  3.  
  4.     #include <QMainWindow>
  5.  
  6.     namespace Ui {
  7.       class MainWindow;
  8.     }
  9.  
  10.     class MainWindow : public QMainWindow
  11.     {
  12.       Q_OBJECT
  13.  
  14.     public:
  15.       explicit MainWindow(QWidget *parent = 0);
  16.       ~MainWindow();
  17.  
  18.     private slots:
  19.       void on_btnTest_clicked();
  20.       void OnTimerTick();
  21.  
  22.     private:
  23.       Ui::MainWindow *ui;
  24.       ulong seconds;
  25.     };
  26.  
  27.     #endif // MAINWINDOW_H
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Qt Code: 
  1. #include "mainwindow.h"
  2.     #include "ui_mainwindow.h"
  3.     #include "opencv2/core/core.hpp"
  4.     #include "opencv2/highgui/highgui.hpp"
  5.     #include "opencv/cv.h"
  6.     #include <QTimer>
  7.     #include <QtCore>
  8.  
  9.     MainWindow::MainWindow(QWidget *parent) :
  10.       QMainWindow(parent),
  11.       ui(new Ui::MainWindow)
  12.     {
  13.       ui->setupUi(this);
  14.     }
  15.  
  16.     MainWindow::~MainWindow()
  17.     {
  18.       delete ui;
  19.     }
  20.  
  21.  
  22.     void MainWindow::on_btnTest_clicked()
  23.     {
  24.       QTimer * timer = new QTimer(0);
  25.       seconds =0;
  26.       connect(timer,SIGNAL(timeout()),this,SLOT(OnTimerTick()));
  27.  
  28.       timer->setInterval(100);
  29.       timer->start();
  30.  
  31.      QThread::sleep(5);//simulating a method which takes 5 seconds to complete
  32.  
  33.      //timer->stop();   
  34.  
  35.     }
  36.  
  37.     void MainWindow::OnTimerTick()
  38.     {
  39.       ui->lblElapsedTime->setText(QString::number(++seconds));
  40.     }
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How can I get the asynchronous behavior, something like what we have in C#? where the Timer runs its own thread of execution?